Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
  • D01G11/00—Disintegrating fibre-containing articles to obtain fibres for re-use
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
  • D02G3/02—Yarns or threads characterised by the material or by the materials from which they are made
  • D02G3/16—Yarns or threads made from mineral substances
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
  • D01G1/00—Severing continuous filaments or long fibres, e.g. stapling
  • D01G1/06—Converting tows to slivers or yarns, e.g. in direct spinning
  • D01G1/10—Converting tows to slivers or yarns, e.g. in direct spinning by cutting
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
  • D01G13/00—Mixing, e.g. blending, fibres; Mixing non-fibrous materials with fibres
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
  • D01G15/00—Carding machines or accessories; Card clothing; Burr-crushing or removing arrangements associated with carding or other preliminary-treatment machines
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
  • D01G15/00—Carding machines or accessories; Card clothing; Burr-crushing or removing arrangements associated with carding or other preliminary-treatment machines
  • D01G15/84—Card clothing; Manufacture thereof not otherwise provided for
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
  • D01G19/00—Combing machines
  • D01G19/06—Details
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
  • D02G3/02—Yarns or threads characterised by the material or by the materials from which they are made
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
  • D02G3/02—Yarns or threads characterised by the material or by the materials from which they are made
  • D02G3/04—Blended or other yarns or threads containing components made from different materials
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
  • D02G3/02—Yarns or threads characterised by the material or by the materials from which they are made
  • D02G3/06—Threads formed from strip material other than paper
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2101/00—Inorganic fibres
  • D10B2101/10—Inorganic fibres based on non-oxides other than metals
  • D10B2101/12—Carbon; Pitch

Definitions

• This invention concerns a novel approach to the production of yarns from carbon fibres. Specifically, the invention provides spun yarns which are obtained from recycled carbon fibres, and methods for the production of these yarns.
• Carbon fibre also has the advantage of considerably lower density when compared with steel, and this makes it an ideal material for applications requiring low weight.
• the properties of carbon fibre such as high tensile strength, low weight and low thermal expansion, make it especially useful in aerospace, civil engineering, military, and motor sports applications.
• it is in carbon fibre reinforced polymers that the material finds the most widespread use.
• WO-A-2007/058298 teaches a recycled composite material made from a waste product of an original composite material, wherein the original composite material comprises a matrix and a carbon fibre structure contained in the matrix, the carbon fibre structure having a three-dimensional network structure.
• the recycled composite material is produced by supplementing the waste product of the original composite material with a matrix which is same as, and/or different to, the matrix contained in the waste material, and then kneading the resulting mixture.
• a spun yarn comprising recycled carbon fibre.
• recycled carbon fibre is taken to be carbon fibre which has been used for a previous application in a material which has reached the end of its useful life.
• the recycled carbon fibre comprises discontinuous carbon fibre and may be recycled from various sources, such as end-of-life waste and manufacturing waste by means of cutting or chopping of these materials.
• the recycled carbon fibre may also include continuous carbon fibre.
• said recycled carbon fibre comprises recycled virgin carbon fibre, which is recovered during manufacturing pipeline activities, and/or reclaimed carbon fibre waste, or recyclate, which comprises carbon fibre recovered from finished composites as end-of-life or manufacturing waste.
• Said recycled carbon fibres may be obtained from any convenient source.
• virgin carbon fibre waste may, for example, be obtained from multi-axial fabric trim, weaving selvedge trim, fibre collected from machine extraction systems, chopped continuous tow, woven fabric and unidirectional fabric, whilst reclaimed carbon fibre waste (recyclate) includes fibre recovered from end-of-life and finished composite materials through removal of resin matrix by means of high temperature processing or other suitable means of separating resin matrix from carbon fibre.
• the spun yarn according to the first aspect of the invention additionally includes at least one other fibre, commonly referred to as a matrix fibre, which may be any natural or synthetic polymer, but preferably comprises at least one thermoplastic resin.
• Suitable thermoplastic resins may, for example, include polyalkenes such as polyethylene or polypropylene, polyesters such as polyethylene terephthalate or polybutylene terephthalate, polyamides, polyethersulphone polymers, or high performance fibres, examples of which include VectranTM, which is an aromatic polyester and is spun from a liquid crystal polymer, and polyaryletheretherketones from the PeekTM range of polymers.
• the recycled carbon fibre for use in this preferred embodiment can be of any length suitable for blending with the other fibres.
• said recycled carbon fibre will have a length in the range from 40-250 mm, but the most preferred length is 80 mm.
• the recycled carbon fibre content of the spun yarn can be from 0.1 -99.9%, preferably 30-80%, by weight.
• said process additionally comprises the step of straightening the fibres, this step being performed after intermingling the fibres, and prior to forming a yarn.
• the process of intermingling the fibres is preferably performed by carding the fibres.
• Carding may be carried out by any of the standard carding techniques involving the use of carding machines such as revolving flats cards and roller and clearer cards, the latter of which are conventionally used for carding longer staple fibres and are well known as worsted, semi- worsted and woollen cards.
• carding is carried out by means of a stationary flat card.
• Said carded fibres are optionally then formed into sheets of the required mass by unit area by bonding using any suitable bonding technique which is well known in the art, such as mechanical bonding, chemical bonding or, preferably, thermal bonding.
• the specific weight per unit area which is suitable for each specific application is determined by reference to parameters which necessarily include the quality of the yarn which is required to be produced and the count of the yarn.
• Said sheets may then be slit into strips of specified width, which can then be twisted either individually as single strips, or together as a multiplicity of strips, so as to form a yarn.
• thermal bonding of the web may be carried out to such a degree wherein twisting is not required, since the strips have sufficient strength for subsequent processing operations, such as weaving, knitting, and the like.
• said carded fibres may be formed into a sliver, and the subsequent process of formation of a yarn may optionally then be carried out by means of the steps of:
• said spinning operation comprises ring spinning, friction spinning, wrap spinning, or any other well known commercial spinning system.
• the sliver formed from said carded fibres may be thermally bonded, slit into strips of specified width and twisted either individually as single strips, or together as a multiplicity of strips, so as to form a yarn, as previously described.
• a further option provides for the thermally bonded sliver to be formed into a thermoplastic prepreg by treatment of the sliver by means of, for example, a heated roller or a thermal environment such as an oven.
• the process of intermingling the fibres is carried out by forming a web by the process of wet-laying, whereby the carbon fibre is intermingled in a fluid, preferably aqueous, medium with at least one other fibre (a carrier fibre) and the composition is then deposited uniformly on a perforated screen or permeable substrate in order to form a sheet material of the required mass per unit area in a process similar to the Fourdrinier paper making process.
• the sheet so formed may have sufficient integrity to be slit into strips without any additional bonding stage; in the alternative a bonding or a bonding stage may be used.
• the sheets thereby formed may then be slit into strips of specified width and twisted either individually as single strips, or together as a multiplicity of strips, so as to form a yarn, in the manner previously disclosed.
• the production of a core yarn is envisaged, said yarn comprising a continuous or discontinuous strand of filament and/or fibres positioned to form the core of the yarn, wherein said core is surrounded by a sheath which comprises staple fibres.
• the first aspect of the invention also contemplates a spun yarn comprising recycled carbon fibre, wherein said yarn comprises a core yarn.
• the core may comprise virgin or recycled carbon fibre, whilst the sheath comprises recycled carbon fibre or recycled carbon fibre blended with a thermoplastic or other suitable fibre.
• the core may comprise a thermoplastic fibre or other reinforcing fibre. Accordingly, the method of the second aspect of the invention may be utilised for the production of a core yarn.
• the recycled carbon fibre utilised in the method of the second aspect of the invention preferably consists of discontinuous virgin carbon fibre which is recycled from various sources, such as end-of-life waste and manufacturing waste.
• the spun yarn produced according to the method of the second aspect of the invention additionally includes other (matrix) fibres which preferably comprise at least one thermoplastic resin, as defined above.
• the recycled carbon fibre for use in this preferred embodiment can be of any length suitable for blending with the matrix fibres.
• said method for the production of a yarn comprising recycled carbon fibre comprises the production of yarn from blends of carbon fibre and other fibres
• said production may either be achieved by initially blending these fibres together during the process of opening and blending of the fibres, or the fibres may be blended during the subsequent twisting or spinning operations.
• Figure 1 is an illustration of a typical stationary flat card which is suitable for the processing of recycled carbon fibres according to the method of the second aspect of the invention
• Figure 2 depicts the geometry of a typical feed system which is suitable for the processing of carbon fibres from various waste streams according to the method of the second aspect of the invention; and Figure 3 shows the preferred orientation of fibres within a sliver produced by a card operating in a process according to the method of the second aspect of the invention.
• the present invention provides spun yarn, and a method for the production thereof, using discontinuous recycled carbon fibre, thereby providing a product and method which are not known from the prior art.
• said discontinuous recycled carbon fibre typically comprises recycled virgin carbon fibre and/or reclaimed carbon fibre waste, or recyclate.
• Preferred sources of recycled virgin carbon fibre include, for example, the following:
• Multi-axial trim - This is available directly from multi-axial processes without the need for cutting to length;
• Weaving selvedge - Carbon fibre may be mechanically separated from fabric selvedge either on a loom or off loom by means of a separate process;
• Extraction waste - Suction waste is available from looms and other processing equipment
• Woven fabric - Fabric can be separated from end of run, trim waste and the like, and the carbon fibres thereby recovered.
• carbon fibre is extracted from end-of-life waste materials comprising polymer matrices by means of a standard industrial process for the separation of a resin matrix from carbon fibre, which typically involves the use of at least one of a thermal treatment, treatment with solvents, use of a fluidized bed, or use of supercritical fluids.
• Recycled carbon fibre which is suitable for use in the method according to the second aspect of the invention for the production of the spun yarn of the first aspect of the invention will preferably have the following features:
• the recycled carbon fibre may be blended with other fibres prior to the carding process.
• These fibres may be made from natural or synthetic polymers and form part of the resin matrix in the finished composite material.
• Other structural reinforcing fibres may also be added, such as glass, a ceramic, a para-aramid (aromatic polyamide), and the like for the purposes of achieving specific performance attributes in the finished composite.
• Carding is a key stage in a method according to the second aspect of the invention and is a well known process whereby a fibre mass of similar or dissimilar fibres can be separated into individual fibres and combined to form a filmy web that is subsequently consolidated into the form of a twistless rope, termed a card sliver.
• Revolving flats cards may be employed for the processing of recycled carbon fibre.
• stationary - or fixed - flat cards as depicted in Figure 1 .
• the flats are positioned at the top of the machine, between the inlet (N1 ) and the outlet (N2).
• the lap of fibres is fed to the licker-in (Q4) which reduces the mass per unit area (QL) and delivers (Q3) it to the cylinder.
• the cylinder and flats are covered with saw-tooth wire clothing. The rotational movement of the cylinder enables the saw-tooth wire clothing of both surfaces to individualise the fibres as the fibre mass moves to the outlet of the card.
• the doffer which may also be fitted with saw-tooth wire clothing or, alternatively, may be equipped with pins, removes the individual fibres, but in the assembled form of a fibre web (i.e. card web). This web may then be consolidated into a sliver.
• the parameters relating to the cylinder are 15 degree front angle, 3.12 mm height and 394 teeth density.
• FIG. 2 there is shown the geometry of the feed arrangement to the card, i.e. the feed roller and feed plate. It is important that the relative arrangement of the feed roller and feed plate to the licker-in roller should be modified correctly so as to appropriately process carbon fibres from particular waste streams. Thus, it is important that the contact point of the licker-in with the carbon fibre is sufficiently distanced from the nip-line of the feed roller and feed plate in order to prevent shortening of fibre length or other damage to the carbon fibre.
• the first heating and drawing zone serves to melt the resin fibres, thereby bonding together the carbon fibres with the polymer matrix whilst being drawn.
• the material cools before entering the second heating and drawing zone, wherein the polymer is heated above its Tg (glass transition temperature) whilst being drawn.
• the process is an adaptation of the melt spinning process for thermoplastic-synthetic fibres, wherein a polymer is heated to the molten state and, during extrusion, it is thinned by drawing. On subsequent cooling it enters a second heating stage, wherein it is further drawn.
• the purpose of this procedure is to highly align the polymer chains. It is known that, in order to align fibres, interfibre shear forces must be generated. In conventional drawing operations, this is achieved by frictional contact between fibres. However, greater shear forces can be generated in a viscous fluid media, such as the molten polymer matrix.
• the spun yarn and method of the present invention display several improvements over the prior art.
• a method is provided for the re-use of waste carbon fibre generated from first use processing activities and reclaimed carbon fibre from end of life and finished composite materials.
• the delivery of value benefits to end users is facilitated by offering the opportunity to substitute virgin carbon fibre materials with staple spun yarn from recycled carbon fibre.
• the scope of market application for carbon fibre is widened through potential substitution of other lower cost reinforcing materials.
• the staple spun yarn from recycled carbon fibre shows the required degree of strength and durability, and can be used in all conventional composite manufacturing operations where virgin yarn is currently employed, such as woven fabric manufacture, unidirectional fabric manufacture, filament winding, pultrusion and the like.
• virgin yarn such as woven fabric manufacture, unidirectional fabric manufacture, filament winding, pultrusion and the like.
• the yarn finds application in the following applications:

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Nonwoven Fabrics (AREA)
• Processing Of Solid Wastes (AREA)
• Inorganic Fibers (AREA)

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Publications (1)

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• 2010
  • 2010-02-05 GB GB1001868.7A patent/GB2477531B/en not_active Expired - Fee Related
• 2011
  • 2011-02-07 US US13/577,141 patent/US9404202B2/en not_active Expired - Fee Related
  • 2011-02-07 JP JP2012551693A patent/JP2013519000A/ja active Pending
  • 2011-02-07 WO PCT/GB2011/050208 patent/WO2011095826A2/en not_active Ceased
  • 2011-02-07 EP EP11704090A patent/EP2531638A2/en not_active Withdrawn
  • 2011-02-07 CA CA2826613A patent/CA2826613C/en not_active Expired - Fee Related

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